It's a simple question of the nature of the work: BSI does systems integration, SAP type projects. Strategy is part of the Business Consulting group and does a pretty good range of corporate strategy, M&A, business architecture etc. 3 things worth bearing in mind ... (1) the strategy groups in different operating groups are different beasts so really challenge yr interviewer about the projects they have done, the calibre of people etc. (2) there is a real effort to specialise the workgroups, so training / career development etc. will be increasingly targetted i.e. you will prob have a very different career depending on the choice you take and (3) strats is a lot harder to get into.
